The short answer: 60°C is the number that matters. Washing at 60°C with detergent kills most bacteria and viruses and wipes out house dust mites — while a 40°C wash kills only about 6.5% of dust mites and leaves most bacteria alive. But here’s the nuance almost no one explains: killing germs and removing them are two different things. Even a cold wash physically flushes away over 90% of dust-mite allergen and dilutes bacteria hugely. So you don’t need a hot wash for everything — you need it for the specific loads that actually require disinfecting.
Modern detergents and eco settings have pushed everyone towards 30°C washing to save energy — which is genuinely fine for everyday freshening. The confusion starts when people assume a cool wash also sanitises. It mostly doesn’t. This guide sets out exactly what different temperatures do to germs and dust mites according to the research, which loads to wash hot, and how to disinfect laundry even when you can’t crank up the heat. Sources are linked at the end.
How we researched this: the figures below come from allergy and laundry-hygiene studies published in the Journal of Allergy and Clinical Immunology and related research, plus established public-health guidance. Full references are at the bottom.
What temperature kills bacteria in the wash?
The consensus from laundry-hygiene research and public-health guidance is clear: 60°C is the threshold for reliably killing most bacteria, viruses and fungi in a wash, particularly with a good detergent and a full-length cycle. Below that, killing power drops off sharply. At 30–40°C, many bacteria and viruses survive the wash — the cycle cleans your clothes and removes a lot of microbes by dilution, but it doesn’t sanitise them.
This is why healthcare and food-hygiene guidance specifies hot washing (typically 60°C or above, often with an oxidising bleach) for items that need to be genuinely decontaminated. Some tough organisms — certain spores and hardy bacteria — can survive even 60°C, which is why disinfection usually pairs heat with detergent and, where needed, bleach. But for ordinary household germs, 60°C does the job that 30°C cannot.
What temperature kills dust mites?
Here the numbers are strikingly precise, because allergy researchers have measured it carefully. House dust mites — a major trigger for allergies and asthma — are killed by heat, not by cold:
- 60°C (140°F) kills essentially all dust mites. In one widely reported study, hot washing killed 100% of dust mites, versus just 6.5% at 40°C [1].
- 55°C and above is the kill zone. Research found all mites were killed by water at 55°C or greater [3].
- Allergen left behind falls with heat, too. One study measured the allergen remaining after washing at 30°C, 40°C and 60°C as 26.8%, 2.4% and 1.3% respectively [3].
So for anyone with dust-mite allergies or asthma, the advice to wash bedding at 60°C isn’t fussiness — it’s the difference between killing the mites and simply giving them a warm bath.
The bit everyone misses: killing vs removing
Here’s the reassuring flip side. Washing does two useful things — it can kill germs (needs heat) and it can remove them (works at any temperature) — and the removing part is powerful on its own. Even a cold wash physically flushes away more than 90% of dust-mite allergen, because the water and detergent lift it off the fabric and rinse it down the drain [2]. The mites may survive a cold wash, but much of the allergen that actually makes you sneeze is carried away regardless.
The same logic applies to bacteria: a 30°C wash won’t sterilise your clothes, but detergent, agitation and rinsing still strip away a large share of the microbes and the sweat and soil they feed on. That’s perfectly adequate for everyday clothes that aren’t a hygiene risk. The trick is knowing which loads need killing and which only need cleaning.
What you should actually wash hot
You don’t need to blast everything at 60°C — that wastes energy and wears out clothes. Match the temperature to the job:
| Wash at 60°C (to disinfect) | 30–40°C is fine (to clean) |
|---|---|
| Bedding and pillowcases (especially with allergies) | Everyday outerwear and jeans |
| Towels, bath mats and flannels | Lightly worn tops and jumpers |
| Underwear, socks and gym kit | Delicates (per the care label) |
| Tea towels, cloths and cleaning rags | Colours prone to fading |
| Anything used during illness (D&V, flu) | Wool and silk (cool/hand wash) |
| Cloth nappies and baby items | Most “eco” everyday loads |
A sensible routine for most homes: everyday clothes at 30–40°C, and a weekly 60°C wash for towels, bedding and underwear. Always check the care label first — a hot wash will shrink wool, damage silk and fade some colours.
How to disinfect laundry without a 60°C wash
Sometimes you need to sanitise something that can’t take 60°C — a delicate item, or a whole wardrobe of cool-wash clothes during illness. You have options that add killing power at lower temperatures:
- Oxygen (activated) bleach — sodium percarbonate, the “oxi” powders. It releases hydrogen peroxide and boosts disinfection even at 30–40°C. Colour-safe, unlike chlorine bleach.
- A dedicated laundry sanitiser or disinfectant — designed to kill bacteria in cool washes; add to the rinse or wash per the instructions.
- A hot tumble dry — the heat of a full drying cycle kills many surviving microbes and dust mites, so drying hot after a cool wash adds a hygiene boost.
- Sunlight — line-drying in direct sun exposes laundry to UV, which has a genuine (if modest) germ-reducing effect and helps with odours.
- Dry thoroughly, fast — damp laundry left in the machine or on an airer regrows bacteria and turns musty; getting it dry quickly is itself a hygiene step.
The low-temperature washing and smelly-machine link
There’s a sting in the tail of always washing cool: it’s a leading cause of smelly washing machines and musty towels. Low temperatures never get hot enough to clear the greasy, bacterial biofilm that builds up in the drum, detergent drawer and door seal — so the machine itself becomes a reservoir that re-soils your “clean” laundry with that damp, sour smell. The fix is a regular hot maintenance wash: run the machine empty at 60–90°C every week or two. See our guides to the best washing machine cleaners and cleaning a washing machine naturally for the full routine.
The bottom line
If your goal is to kill germs and dust mites, 60°C is the magic number — 30–40°C simply doesn’t get there (it kills only around 6.5% of dust mites and leaves most bacteria alive). But if your goal is everyday cleanliness, a cool wash is genuinely fine, because washing physically removes the great majority of allergen and soil at any temperature. So run everyday clothes cool to save energy, reserve 60°C for towels, bedding, underwear and illness laundry, reach for oxygen bleach or a hot tumble dry when you need extra hygiene at low temperatures — and give your machine a hot maintenance wash so it doesn’t undo all your good work.
Frequently asked questions
What temperature kills bacteria in laundry?
Around 60°C. Washing at 60°C with detergent kills most bacteria, viruses and fungi, which is why it’s the standard recommendation for hygienically cleaning towels, bedding and illness laundry. Cooler washes at 30–40°C clean clothes and remove many microbes by dilution but don’t reliably kill them.
Does washing at 30 or 40 degrees kill germs?
Not reliably. At 30–40°C many bacteria and viruses survive the wash — the cycle removes a good share of them along with dirt and sweat, but it doesn’t sanitise. For genuine disinfection you need 60°C, or you can add an oxygen-based (activated) bleach or laundry sanitiser to a cooler wash and dry it hot.
What temperature kills dust mites in bedding?
55–60°C. Studies found all house dust mites were killed at 55°C and above, and a 60°C wash killed essentially 100% of them versus only about 6.5% at 40°C. If you have a dust-mite allergy, wash bedding at 60°C; if the fabric can’t take it, a cool wash still rinses away most of the allergen, and a hot tumble dry helps kill the mites.
Does a cold wash actually clean clothes?
Yes, for everyday purposes. Modern detergents work well in cold water, and washing removes the majority of soil, sweat and allergen at any temperature — even a cold wash flushes away over 90% of dust-mite allergen. Cold washing just doesn’t disinfect, so it’s ideal for ordinary clothes but not the right choice for towels, bedding or anything used during illness.
How should you wash towels and bedding hygienically?
Wash them at 60°C with a good detergent, don’t overload the machine, and dry them promptly and thoroughly. Towels in particular stay fresher when washed hot and dried quickly, because they hold moisture and bacteria. Adding oxygen bleach helps with both hygiene and brightness.
Will washing hotter stop my laundry smelling musty?
Often, yes. Musty “clean” laundry is usually caused by bacteria and biofilm surviving cool washes — both on the fabric and inside the machine. Washing towels and bedding at 60°C, drying laundry quickly, and running a regular hot maintenance wash to clean the machine itself together fix most persistent laundry smells.
Related reading: does vinegar actually disinfect? and are kitchen sponges the dirtiest thing in your home?
References
- “Hotter Is Better For Removing Allergens In Laundry” (American Academy of Allergy, Asthma & Immunology research). ScienceDaily, 2007. sciencedaily.com
- McDonald L.G. & Tovey E. “The role of water temperature and laundry procedures in reducing house dust mite populations and allergen content of bedding.” Journal of Allergy and Clinical Immunology, 1992. pubmed.ncbi.nlm.nih.gov
- “Mite and mite allergen removal during machine washing.” Journal of Allergy and Clinical Immunology, 2003. jacionline.org
This article summarises published research and public-health guidance for general information. For clinical allergy or infection-control advice, follow NHS or a qualified professional’s guidance. To kill dust mites in carpets and mattresses (not just bedding), see whether steam cleaning kills germs and dust mites.
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